Overload relay for electric heaters



I v 1,635,674 y 1927' L. P. HYNES OVERLQA'D RELAY FOR ELECTRIC HEATERS Filed Aug. so, 1922 Qwuehtoz 7 Lee R Hynes, Wat hm 3% 53a. @9422;

Patented July 12, 1927.

' UNITED STATES 1,635,674 PATENT OFFICE.

LEE 1. HYNEB, 01' ALBANY, NEW YORK, ASSIGNOR TO CONSOLIDATED CAR-HEATING OOIPANY, O1 ALBARY, NEW YORK, A CORPORATION OF WEST VIRGINIA.

OYERLOLD BILLY FOR ELECTRIC HEATERS.

Application lied unit 80, 1922. Serial No. 585,304.

For a detailed description of the resent form of my invention, reference may had to the followin specification and to the accompanying rawings forming a part 6 thereof.

My invention relates to a rotectivedevice for electric heaters which 1s in the nature of an overload relay which, although a unitary'device, will respond to an excessive cur- 10 rent in an one of a series of heater circuits such as might be produced by an accidental ground connection at a point in the circuit sufliciently near the positive terminal to cause a material reduction in the resistance of the l circuit and a resulting current of a dangerous magnitude.

Referring to the drawing, 0 0 O, 0 represent a series of parallel control levers havin a common pivot in N and each one normal pressed upwar by its individual spring Pivotally mounted adjacent to t e control levers is a latch lever J weighted at one end and widened at the same end so as to rest upon and engage the contiguous ends of all of said levers. The other end of the lever J is provided with latch Y which normally engages the end of a switch lever H which is pivoted at K and provided with a spring H that constantly tends to sepaao rate the switch contacts L L. To the opposite end of each of the levers O, O, O, O is attached an expansible tension wire of German silver or other suitable allo which will expand rapidly when heated. e several wires are marked B, B, B and B and they are severall connected to adjustable terminal screws 1, E, E, E, which, in turn', are severally connected to heater circuits each of whlch contains a number of heater coils in series.

Under normal conditions the switch will be latched shut connecting the several heater circuits to the main clrcuit by the closure of contacts L L. Thecurrent will then flow from H, b jumper M, to the spindle N on which t e oup of levers is pivoted. Thence it will ow to each of the heater circuits through respective wires .13, B,B B. If one of the heatercircuits becomes rounded, as at the point X, the result will to short-circuit the last section of heater resistance and thereby cause a material increase in the current which flows to that particular heater-circuitthrough ten:

sion wire B. Thereupon that wire will ex.- pand allowing the left end of lever O to drop and the right end to rise,-- liftin lever J and unlatching switch-lever'H, whic then acts to open the main supply circuit at contacts L L. In like manner a ground on any one of the several heater circuits will produce the breaking of the supply circuit for all the hold them against movement under the spring tension thereon, sothat movement of t e leversis'automatically controlled by said thermal means and a latch lever having one end engaging all of said control levers and the other end in engagement with said switch.

2. An overload relay for a plurality of electric heater circuits comprising a supply switch for two or more heater circuits, a plurality of spring-pressed control levers, one for each circuit, thermal means engaging the respective levers at one end to normally hold t em against movement under the spring tension thereon, so that movement of t e levers is automatically controlled by said thermal means and a latch. member having a weighted end resting on all of said control levers, the other end of said latch lever being in normal engagement with said switch.

3. An overload relay for a plurality of electric heater circuits comprising a supply switch for two or more heater circuits, aplurality of spring-pressed control levers, one for, each circuit,thermal means enga ingithe respectivelevers at one end to normally old them against movement under the springtension thereon, so that movement of the lovers is automatically controlled by said thermal means and a latch having a widened portion at one end engaging all of said control levers and having its other end in normal engagement with saidsw'itch.

4. An overload relay for a plurality of electric heater circuits comprising a supply switch for two or more heater. circuits, a

supply switch lever normally biased to move to open circuit position, aplurality ofcontrol levers one of which is included-in each of said circuits, a latch lever having one end engaging all of said control levers, its other end being in engagement with said supply switch lever to hold said lever in closed circuit position, means normally tending to move said control levers in a direction to disengage the latch lever from the *said switch lever, and thermal Wires engaging the respective control levers at one end to normally hold them against movement in opposition to the means normally tending to electric heater circuits comprising a supply switch *for two or more heater circuits, a supply switch lever normally biased to move trol levers, one-for each circuit, a latch lever having a wldenedand weighted portion restmg upon one end of all of sald control levers, the other end of the latch lever engaging said supply switch lever, springs tending to'move the levers in a direction to cause disengagement of the latch lever, and thermal wires to hold said levers against movement under the tension of said springs. Signed at Albany, county of Albany and State of New York, this 23rd day of August, 1922.

L. P. HYNns.

to open circuit position, a plurality of con- 

